Allegedly there's a way to, but 1) it's difficult to configure 2) you won't be the only one with the cheats access, and anyone can take over your server. If you use Sourcemod you can give yourself admin and then use whatever cheats you'd like through that.

Yeah I have heard there is a way but in the case you succeed by changing the cvar withoutit crashing, anyone with the know how could come in spam zombies / weapons or just simply type sv_crash and take down the server. That and they get their in game wallhacks aswell.